I’ve noticed an issue where you cannot save any changes that you make to a modular block without first changing the name of the block. You can leave the model ID as it is but you have to change the name in some way for the save button to become clickable. I’ve just been changing it slightly and then opening it up and changing it back again but this doesn’t seem right so I wanted to flag it!
Ah I see.
Adding new fields gets saved automatically so the big save button is actually only referring to the name and ID. So not a bug at all - just a bit confusing from a UX point of view.